Fast Piggie: add 15ms pre-flash gap before image reveal

app/games/fast-piggie/index.js

@@ -240,6 +240,9 @@ let _clickEnabled = false;
 let _selectedWedge = -1; // for keyboard navigation
 let _hoveredWedge = -1; // for mouse hover highlighting
 let _roundTimer = null; // setTimeout handle
+let _imageFlashTimer = null; // setTimeout handle before image flash
+// Give the board a small lead-in so previous wedge highlights clear before image flash starts.
+const ROUND_IMAGE_FLASH_DELAY_MS = 15;
 
 /**
  * Updates the score, round count, and display time in the UI.
@@ -302,6 +305,15 @@ function _highlightKeyboardSelection() {
 function _runRound() {
   if (!game.isRunning()) return;
 
+  if (_imageFlashTimer) {
+    clearTimeout(_imageFlashTimer);
+    _imageFlashTimer = null;
+  }
+  if (_roundTimer) {
+    clearTimeout(_roundTimer);
+    _roundTimer = null;
+  }
+
   _clickEnabled = false;
   _selectedWedge = -1;
   const round = game.generateRound(game.getLevel(), game.getSpeedLevel());
@@ -319,19 +331,23 @@ function _runRound() {
   _currentRound = { ...round, slotAssignment };
 
   const { width, height } = _canvas;
-  drawBoard(
-    _ctx, width, height, wedgeCount, imageCount, _images,
-    outlierWedgeIndex, true, slotAssignment,
-  );
+  clearImages(_ctx, width, height, wedgeCount);
+  _imageFlashTimer = setTimeout(() => {
+    _imageFlashTimer = null;
+    drawBoard(
+      _ctx, width, height, wedgeCount, imageCount, _images,
+      outlierWedgeIndex, true, slotAssignment,
+    );
 
-  _roundTimer = setTimeout(() => {
-    clearImages(_ctx, width, height, wedgeCount);
-    _currentRound._imagesHiddenAt = Date.now();
-    _clickEnabled = true;
-    _hoveredWedge = -1;
-    _selectedWedge = -1;
-    _canvas.focus();
-  }, displayDurationMs);
+    _roundTimer = setTimeout(() => {
+      clearImages(_ctx, width, height, wedgeCount);
+      _currentRound._imagesHiddenAt = Date.now();
+      _clickEnabled = true;
+      _hoveredWedge = -1;
+      _selectedWedge = -1;
+      _canvas.focus();
+    }, displayDurationMs);
+  }, ROUND_IMAGE_FLASH_DELAY_MS);
 }
 
 /**
@@ -614,6 +630,10 @@ export default {
    * @returns {Promise<object>} Game result
    */
   async stop() {
+    if (_imageFlashTimer) {
+      clearTimeout(_imageFlashTimer);
+      _imageFlashTimer = null;
+    }
     if (_roundTimer) {
       clearTimeout(_roundTimer);
       _roundTimer = null;
@@ -652,6 +672,10 @@ export default {
    * Reset the game to its initial state.
    */
   reset() {
+    if (_imageFlashTimer) {
+      clearTimeout(_imageFlashTimer);
+      _imageFlashTimer = null;
+    }
     if (_roundTimer) {
       clearTimeout(_roundTimer);
       _roundTimer = null;

app/games/fast-piggie/tests/index.test.js

@@ -1185,6 +1185,22 @@ describe('_triggerFlash and next-round timers', () => {
   });
 });
 
+describe('_runRound image flash timing', () => {
+  const mockedDisplayDurationMs = 2000;
+
+  it('schedules the image flash 15ms after wedges are hidden', () => {
+    const setTimeoutSpy = jest.spyOn(globalThis, 'setTimeout');
+    try {
+      plugin.start();
+      expect(setTimeoutSpy).toHaveBeenCalledWith(expect.any(Function), 15);
+      jest.advanceTimersByTime(15);
+      expect(setTimeoutSpy).toHaveBeenCalledWith(expect.any(Function), mockedDisplayDurationMs);
+    } finally {
+      setTimeoutSpy.mockRestore();
+    }
+  });
+});
+
 // ===========================================================================
 // loadImages onerror path and init() .catch() fallback
 // (f[4] and f[33] in index.js)